As seen in FIG. 1 and addressed in Prosthetic Aortic Valve Replacement (Hans-Hinrich Seivers, Journal of Thoracic and Cardiovascular Surgery, 2005, Vol. 129: pp. 961-965), the aortic root includes segments of an ellipse where valve cusps are attached to the wall of the aorta and are supported by thickened, dense fibrous tissue. These fibrous thickenings form an “anatomic annulus” that has a crown-shaped configuration. In FIG. 1 this crown is depicted by the undulating dashed line of element 110. The three elliptical portions of the crown confine the sinuses on one side as the most proximal part of the aorta and the intervalvular trigones on the other side, which at least hemodynamically belong to the left ventricle. The dense fibrous tissue of the “anatomic annulus” is strong and provides an anchor for suturing a prosthetic valve within the aortic root.
There is no solid continuous anatomic circular annulus or ring in which to place the anchoring sutures as a geometric exact counterpart for the perfectly circular sewing rings of conventional prostheses. A “basic annulus” (see dashed line of element 105 of FIG. 1) consists of the nadirs of the elliptical attachments of the cusps (see element 115 as an example of one such nadir), the septal muscle, the ventricular membranous septum, and the distal end of the aortomitral curtain, together termed sometimes the ventriculoarterial junction and defining the smallest cross-sectional area between the left ventricle and the aorta. As such, this “basic annulus” defines the width of the root as measured from the sizers and also the seating of the conventional circular prostheses because the prostheses are fixed with sutures through the nadirs of the annulus.
A conventional implant technique seats the prosthetic valve along annulus 105. The sewing ring of the valve is then sutured through the nadirs of the annulus. This restricts the surgeon to placing attachment sutures in roughly a two dimensional plane (i.e., along ring 105 with little vertical (i.e., superior/inferior) variance due to the narrow sewing ring 120). FIG. 2 includes a conventional device with a narrow sewing ring 220. The attachment feature of the ring, namely section 231, may be approximately 0.16 inches in height. This is approximately 38% of the entire height 232 (e.g., 0.44 inches) of the valve.
This two dimensional attachment methodology results in a general “flattening” of the annulus region. In other words, rings 110 and 105 are flattened together in some instances. Doing so may change the hemodynamic flow of blood upon entering/exiting the prosthetic valve. Specifically, when the surgeon seats the valve he or she must sew along line 105 of FIG. 1 because that is where the valve's sewing cuff lies. However, fibrous tissue is located along dotted line 110. To access the fibrous tissue (suitable for holding sutures) at line 110 the surgeon attaches sutures along dotted line 110 and then pulls the annulus up/down (i.e., lines 105 and 110 together) to get lines 105 and 110 in the same plane. As a result, the conventional attachment methodology and sewing rings generally “flatten” the annulus region.